In a modern data processing unit, such as an electric computer, a magnetic tape or card is generally used as a medium for recording information. In this case, a sensing marker which has a predetermined length and width and which is of a thin film having an aluminum layer deposited thereon in a vacuum is adhered on a magnetic tape or card at a predetermined position according to the rules in Industrial Standards, such as JIS, so that the beginning of the tape or the end of tape can be detected by detecting the sensing marker.
After such magnetic tape has been repeatedly used, the ends of the tape, particularly the beginning end of the tape, may become damaged, and then, it becomes very difficult to properly thread the tape in a magnetic tape unit of an electric computer. To facilitate easy threading of the tape, certain lengths of the damaged tape ends are cut. However, after several cutting operations, the distances between the ends of the tape and the sensing markers become too short to satisfy the above-mentioned rules, and then, it is impossible to thread the tape in the magnetic tape unit. Accordingly, it is necessary that new sensing markers are adhered again on the tape.
In a conventional method, a sensing marker is manually removed from a backing liner without any assistance of an appliance by holding one end of the sensing marker by means of fingers of one hand and by pulling the liner straight down by means of fingers of the other hand. The removed sensing marker is then applied to the back side of the magnetic tape as close to the edge as practical without overlapping therewith. However, it is a very troublesome operation because the sensing marker is thin and flexible, and therefore, the sensing marker may be creased easily. When the sensing marker is improperly applied to the magnetic tape, a certain length of the tape should be cut again because the removal of the sensing marker from the tape is not easy.